Overhead valve internal combustion engines



July 12, 1960 E. R. PAYNE OVERHEAD VALVE INTERNAL coMBus'rIoN ENGINES 2Sheets-Sheet 1 Filed May 5, 1959 my entor Bywqm,

A Horn e ys July 12, 1960 E. R. PAYNE OVERHEAD VALVE INTERNAL coMsusTroNENGINES 2 Sheets-Sheet 2 Filed May 5, 1959 Vrh a. ,a

A ltorneyg United States Patent O OVERHEAD VALVE INTERNAL COMBUSTIONENGINES Eric R. Payne, Northfield, BirminghamEngland, assignor to TheAustin Motor Company Limited, Birmingham, England FiledvMay s, '1959,Ser. No. 811,115 claims priorimapplicaon Great Britain May so, 195sl 1Claim. (Cl. 1223-55) This invention relates to overhead valve internalcombustion engines of the kind in which the cylinder block is formedwith cylinder bores inclinedk at a small angle, alternately one to -theleft kand one to the right, with respect to a vertical plane(hereinafter referred to as the centre plane) in which the crankshaftaxis is disposed, the arrangement being such as to enable a compactarrangement of cylinder head and valve operating mechanism to beobtained.

In an engine of the kind referred to, as hitherto proposed, thecombustion chambers were formed in the cylinder head and the camshaftfor operating the valves was mounted in bearings fixed to the top of the'cylinder block with its axis in the centre plane, whilst said bearingscarried vertical guides in the centre plane fortappets which, throughpush rods, operated valve rockers mounted on rockershafts to eithersideof said plane. With this previously proposed construction, the cylinderhead was formed along its centre with a vertical throughrslot be-4 tweenthe combustion chambers to accommodate the camshaft bearings on thecylinder block and the associated tap-pet guides and push rods.

A multi-cylinder engine of the kind referred to, according to thisinvention, is characterised in that the combustion chambers are affordedwholly hy the upper ends of the cylinder bores, that the camshaftwithits laxis in the centre plane is mounted in bearings which are formed inor carried by the cylinder head at a position low down in the latter,and in that the rockers which operate the valves to either side of saidplane are actuated by tappets which operatein vertical guide boresformed in the cylinder head with their axes in the centre plane.

The invention will now be more fully described with reference to theembodiment shown in the accompanying drawings; in which:

Fig. l is a fragmentary end elevation, partly in section, of afour-cylinder overhead valve internal combustion engine, and Fig. 2 is aplan view thereof with parts of the valve gear omitted so as to show theconstruction more clearly.

Referring to the drawings, the engine comprises a cylinder Ablock 110formed with the four cylinder bores 11 which are inclined at a smallangle, alternately one to the left and one to the right, with respect tothe centre plane, each of said bores '11 being fitted with a piston 12'operated by a connecting rod 13 from the engine' crankshaft 14 which ismounted in end bearings 15 with its axis in said centre plane.Surmounting the cylinder block lo is a cylinder head casting 16 whichhas its undersurface or joint face machined flat so that the combustionchambers are afforded wholly by the upper ends of the cylinder bores 11,the crowns of the pistons 12 being stepped as shown at 17 in Fig. 1.

The cylinder head casting 16 is cored to afford for the two cylinders oneither side of the said centre plane separate exhaust ducts 18, one foreach cylinder, which run out into the corresponding or adjacent sideface of said casting 16 for connection `to the :branches of acomr2,944,536 .Patented July 1,2, 1960 'fi-Ce.

mon exhaust manifold 19', and, between the two exhaust ducts 18on'eitherside, .said casting |16 is 'cored to aord two suction or inletducts 20, one for each cylinder, which runite and run out inthecorresponding or adjacent side face of said casting 16 for connection toa separate carburetterk 21.

The inner ends of the exhaust ducts 18 and suction ducts 2i? arecontrolled -by spring-loaded poppet type valves 22, the stems of Whichare mounted in stem guides 23:V which are tted in vertical bores 24vformed in the cylinder Ihead casting 16.

A camshaft 24, which is positively driven from the engine crankshaft 14in conventional manner, operates the valves 22`through tappets 25 andassociated short push rods 26 which operate on the inner or tail ends ofvalve rockers 27. This camshaft 24 -has its axis in the said centreplane and is mounted in bearings 28 iixed in a cored-out longitudinalhousing 28X at a position low down in the cylinder head casting v16,whilst the tappets 25 which actuate the rockers 27 are mounted inverticali which is sleeved upon said rockershaft 30 and operates betweenthem and one of said bearings 31. Each of ther two rockershafts 30 isdisposed 'between the centre plane and the two sets of valves 22 whichare actuated by its rockers 27, and the sets or pairs of rockers 27 oneach vrockershaft Sli are, of course, oppositely disposed to those onthe other rockershaft 30, so that the inner or tail ends of all therockers 27 can be actuated by the respective push rods 26. n

The invention lends itself to a very compact cylinder head, camshaft andvalve gear assembly by virtue of mounting the camshaft in bearingscarried in the cylinder itself, the operation of the valve rockers bytappets and short push rods, and utilising the upper ends of thecylinder bores as the combustion chambers so that the undersurface canbe machined flat and coring of the cylinder head casting is reduced orsimplified.

Having fully described my invention, what I claim and desire to secureby Letters Patent is:

For use with a V-type multi-cylinder overhead valve engine having lacylinder lblock provided with cylinder bores, a cylinder head having awholly flat lower or joint face adapted to be secured to the upper partof said block, said at surface having exhaust and inlet ports therein,

said head being cored to provide separate exhaust ducts and separateinlet ducts on either side of a center plane 4through said head, saidexhaust and inlet ducts extendingfrom the respective exhaust and inletpor-ts to the respectively adjacent side faces of the cylinder head,valves positioned on either side of said center plane and carried bysaid head for controlling said suction and exhaust ducts, a camshaftoperative entirely within the lower portion of said head with the axisthereof disposed in said center plane, a pair of separate rocker shaftson said head y' (References on following page) 2,94%,536 3 4` ReferencesCited in the le of this patent 1,531,430 Wrentmore Mar. 311, 1925MCGUWCIJ. et al. June 1,293,279 Wilbee Feb. 4, 1919 FOREIGN PATENTS'1344338561 :Townsend Iam. 30; 1.923 5 336,841 Great Britain Oct. 23,1930 MAM-

